Technological enhancement of Chile’s mining supervision through multitemporal satellite-based monitoring of hydrological regimes in tailings deposits.

The technological strengthening of mining oversight constitutes a key pillar for modern management of the geotechnical and environmental risks associated with tailings storage facilities in Chile. In this context, the development of a multitemporal satellite monitoring system is presented to support the capacities of the Chilean State, implemented by the National Geology and Mining Service of Chile (SERNAGEOMIN), for the continuous control of surface hydrological regimes in mining tailings, using cloud-based analytics through Google Earth Engine and Sentinel-2 data for the period 2017–2025.

The methodology is based on the systematic calculation of the Normalized Difference Water Index (NDWI) over dense time series, incorporating adaptive annual thresholds derived from spatial percentiles and metrics of water presence frequency, standard deviation, and coefficient of variation. Based on these indicators, a dynamic classification is implemented to differentiate permanent, seasonal, intermittent, highly variable, and hydrological risk zones, complemented by a static surface moisture classification based on NDWI ranges.

The system integrates interactive year-by-year visualization, automated generation of surface statistics, geospatial export of cartographic products, and intra-annual animations of hydrological behavior, facilitating trend analysis, detection of anomalous events, and objective validation of information reported by mining operators.

The results demonstrate the potential of multitemporal remote sensing as a strategic tool to modernize public mining oversight, optimize inspection prioritization, and strengthen evidence-based decision-making, contributing to more preventive, efficient, and transparent management of risks associated with tailings in Chile.